1. Field of the Invention
The invention relates to melt blown webs or fabrics and more specifically to thermally stable, shrink-resistant polyester melt blown webs or fabrics.
2. Discussion of the Background
The market for melt blown fabrics is growing in the United States and Europe due to the versatility of these fabrics. Melt blowing is a means for converting a polymer directly into a nonwoven fabric. Currently polyolefin polymers and especially polypropylenes are primarily used as materials for melt blown fabrics. However, the demand is apparent for higher temperature, higher strength properties that cannot be met with polyolefin resins.
Polyester polymers would be a natural choice of material for melt blown fabrics due to their high level of acceptance and excellent performance in textile and nonwoven end uses. However, polyester melt blown webs currently available have the disadvantage of excessive shrinkage when the fabric is exposed to elevated temperatures. For example, during ironing, a poly(ethylene terephthalate) polyester fabric would be exposed to temperatures above the glass transition temperature of the polyester causing it to shrink.
There is thus a need for a dimensionally stable (i.e. shrink resistant) polyester melt blown web or fabric material.